[Synthesis, biological activity and conformation of enkephalin analogs structurally related to kyotorphin].

[D-Arg2,Leu5]Enkephalin and two series of its N-terminal short-chain analogues with a free and modified C-terminal carboxylic group, viz. amides and ethyl esters of tri- and tetrapeptides, were synthesized in solution and by solid-phase method. Their analgesic activity, assayed by the "tail pinch" method following intracisternal and intravenous administration to mice, was compared with activity of enkephalins and morphine.

[Conformational aspects of the molecular mechanism of action of bradykinin. II. Conformation and selectivity of action of bradykinin cycloanalogs].

Conformation energy calculations performed for cyclo[(epsilon-lysine1, glycine6)]bradykinin and cyclo-epsilon-kallidin indicate the absence of spatially equivalent low-energy structures for bradykinin and cyclobradykinin molecules, whereas cyclokallidin has conformations similar to the "biologically active" ones for bradykinin that are implicated in binding to both B1 and B2 type receptors.